I don't play with the kids at the park either as I need to be watching them all at once and the best way to do that is to sit or stand back and watch and make sure everyone is playing in the appropriate area, manner, etc. I do talk to other providers at the park, but I talk with my eyes on the kids at all times and I would certainly make sure a 16 month old is not climbing a ladder etc. My younger dcks are not allowed on the play structures until the are more aware of danger and able to climb, etc.